Fluid pressure brake



; Dec. 17,1935. L. K slLLc ox 2 9 3 1 FLUID PRESSURE BRAKE Filed Marchso} 1934 v Patented Dec. 17, 1935 FLUID PRESSURE BRAKE Lewis K. Sillcox,Water-town, N. Y., assignor to The New York Air Brake Company, a'corporatlon of New Jersey Application March 30, 1934, Serial No.718,268

12 Claims. (01. 303-6) This invention relates to braking mechanisms andparticularly to fluid pressure ibrakes for high speed trains of themodern stream lined type.

In the operation of such high speed trains one of the major problems isto ensure stopping distances short enough to permit operation of highspeed trains on tracks equipped with block signals characterized by thepresent signal spacing. The maximum retardation practicable with wheelbrakes does not give stopping distances as short as would be desirablein some emergencies.

The p rp se of the present invention is to produce a wind resistancebrake which operates very efiectively at high train speeds, andfunctions to apply a retarding force preferably, but" not necessarily,exclusiveLv at or near the rear of the train.

Another feature of the invention is the provision of means to bring thewind resistance brake into action as an incident to an emergencyapplication of the wheel brakes and then to take it 'out of action'asthe train slows down.

A preferred embodiment of the invention will now be described byreference to the accompanying drawing, in which,

Fig. 1-is a side elevation of the rear portion of a stream lined car,with the invention applied. Fig. 2 is a plan view of the same, showingthe position assumed by the vanes when projected.

Fig. 3 is a section on the line 33 of Fig. 1',

showing in diagram the relation between a brake cylinder which serves toapply wheel brakes and the motor which projects and retracts the vanes.

A portion of a passenger car body is indicated at 6, the rear end beingtapered according to known principles of stream lining, as indicatedat 1. The rear truck is shown at 8 and two wheels at 9. Fluid pressurebrakes are applied to the wheels, 9, but arenot visible on Fig. 1.

A series of vanes H are mounted in guides 12, so as to be capable ofbeing projected through slots in the car wall into'the stream of airadjacent the car. When retracted the ends of the,

vanes H are flush with the outer surface of the car wall.

These vanes- H are located in a plane indicated by the line 3-3 in Fig.1, and transverse to the tapered rear end of the car- The distance thevanes may be projected is such that their extremities lie preferablywithin the maximum transverse dimensions of the car, and in any case arewithin the clearance limits of the track upon which the car runs.

The vanes II are actuated by rotating reversely, through a moderateangle, a disk l3 journaled at I 4 and connected by links is withrespective vanes II. A double-acting fluid-pressure actuated pistonmotor having a cylinder i6 and piston I1 is connected by lever l8pivoted at l9 and link 2|, to rotate the disk l3 in reverse cation willbe severe enough initially to shift directions. A compression spring 22may be used to exert a moderate retracting force on the piston andconsequently on the vanes.

Pressure fluid to actuate the motor is supplied from any suitable sourcethrough pipe 23, to a distributing valve 24* of the balanced piston typeenclosed in'valve chest 23. This valve is shown in Fig. 3 as of theinside cut-oif'and end exhaust (downward) projecting vanes ll.

15 is shifted to the right the piston moves-outward In Fig. 3 is shown abrake cylinder 29 'arrangedto operate wheel brakes typified by a por 9tion ofthe foundation brake gear 30. Air to ,op- 20 crate cylinder 29arrives through pipe 3| from any suitable brake valve (not shown). I

A branch of pipe 3| leads to cylinder 32 so that pressure in cylinder 29also acts on cylinder 32 .to force piston 33 to the leftagainst theresistance of a loading spring 34. Spring 34 is initially so stressedthat it, yields only after emer- Between piston rod 35 and valve stem 33(com nected to valve 24) is aquick throw device comprising a housing"having'a groove in which a contractile annular spring 33 is confined.Spring 33 encircles a reversely tapered cam 39 and-if forced over themiddle portion of the cam reverses its reaction on the cam. 7

Thus as piston 33 moves to the left it first urges valve 24 to the left,but at a critical point in the pistons motion the spring 33-rides overthe large diameter of the cam and snaps valve 24 to the right." Similar,but reverse action, takes place on reverse motion of piston 33. Thusvalve 24 is always urged to one or the other limit of motionand shiftssuddenly wavering or uncertain action is avoided; I V v The use of aquick throw mechanism between piston 33 andvalve 24 is desirable toensure pre-. cise operation, but the specific form of the quick throwmechanism ation.

In ordinary applications the pressures in cylinder 29 will not be greatenough to shift valve 24 to operate piston l1, but anemergencyapplivalve 24' and cause vanes II to be projected.

It is common practice in theair brake art, particularly in high speedservice, to provide automatic means which gradually reduce the intensityof an emergency application, so that the wheels will not lock as thetrain slows. The pressothatall sure in cylinder 29 may be so controlled,for example by the high speed vent valve H, with the result that vanesII will be projected at the commencement of an emergency applicationwhen train speed is high and consequently when the vanes are highlyeffective; and then retracted as the result of reduction of brakecylinder pressure. This occurs after the train slows,

but before it stops, and while the wheel brakes remain applied.

What is claimed is,-

1. The combination of a vehicle having primary braking means andsecondary braking means; a brake cylinder for actuating said primarybraking means; reversible motor means for shifting said secondarybraking means between active and inactive positions; and meansresponsive to brake cylinder pressure for controlling said reversiblemotor means.

2. The combination of a vehicle having primary braking means andsecondary braking means; a brake cylinder foractuating said primarybraking means; reversible motor means for shifting said secondarybraking means between active and inactive positions; and meansresponsive to brake cylinder pressure for controlling said reversiblemotor means, and arranged to function as brake cylinder pressure passesabove and below a critical value to render said secondary means activeand inactive.

3. The combination of a vehicle having primary braking means andsecondary braking means; a brake cylinder for actuating said primarybraking means; reversible motor means for shifting said secondarybraking means between active and inactive positions; means responsive tobrake cylinder pressure for controlling said reversible motor means, andarranged to function as brake cylinder pressure passes above and below acritical value to render said secondary means active and inactive; andmeans for gradually reducing brake cylinder pressure from a value above,to a value below, said critical value.

4. The combination of a vehicle having friction brakes; a brake cylinderfor applying said brakes; wind, resistance braking means; motor meansfor shifting the last-named braking means between active and inactivepositions; and means responsive to brake cylinder pressure for actuatingsaid motor means.

5. The combination oi a vehicle having friction brakes; a brake cylinderfor applying smd brakes; wind resistance braking means; motor means forshifting the last-named braking means between active and inactivepositions; and means responsive to brake cylinder pressure for actuatingsaid motor means, and arranged to function as brake cylinder pressurerises above and falls below a criticai value to render said d resistancebraking means respectively active and inactive.

6. The combination of a vehicle-having friction brakes; a brake cylinderfor applying said brakes; wind resistance braking means; motor means forshifting the last-named braking means between active and inactivepositions; means responsive to brake cylinder pressure for actuatingsaid motor means, and arranged to function as brake cylinder pressurerises above and falls below a critical value to render said wind resistance braking means respectively-active and inactive; and automatic meansfor gradually reducing brake cylinder pressure: to a value below saidcritical value. 1

7. The combination of a vehicle having friction brakes; a brake cylinderfor applying said brakes; wind resistance braking means; reversiblefluid pressure motor means for shifting the last named braking meansbetween active and 5 inactive positions; a distributing valvecontrolling the reversal of said motor; a loaded abutment subject tobrake cylinder pressure; and a quick throw actuating connection betweensaid abutment and said distributing valve. 10

8. The combination of a vehicle having friction brakes; a brake cylinderfor applying said brakes; wind resistance braking means; reversiblefluid pressure motor means for shifting the last named braking meansbetween active and 15 inactive positions; a distributing valvecontrolling the reversal of said motor; a loaded abutment subject tobrake cylinder pressure; a quick throw actuating connection between saidabutment and said distributing valve; and automatic 20 means forgradually reducing brake cylinder pressure from an intensity at whichthe wind resistance brake is rendered active to an intensity at which itbecomes inactive.

9. The combination of avehicle; a plurality of 5 wind resistance vanes;means for guiding said vanes between active and inactive positions; ashiftable member; operative connections between said .member and vaneswhereby shifting of the membershifts said vanes in unison; and a 0reversible double acting fluid pressure motor for shiftingsaid member.

10. The combination of a vehicle; a plurality of wind resistance vanes;means for guiding said vanes between active and inactive positions; a 35shiftable member; operative connections between said member and vaneswhereby shifting of the member shifts said vanes in unison; a reversiblemotor for shifting said member; a reversing valve controlling saidmotor; friction 40 braking means; and means responsive to -a criticalintensity of the force with which said friction braking means areapplied, operatively connected to actuate said reversing valve.

11. The combination of a vehicle; a plurality of 45 wind resistancevanes; means for guiding said vanes between active and inactivepositions; a shiftable member; operative connections between said memberand vanes whereby shifting of the member shifts said vanes in unison; areversible 50 double acting fluid pressure motor for shifting saidmember; a reversing valve controlling said motor; friction brakingmeans; valve actuating means shiftable proportionally to the energize.-tion of-said friction braking means; and a'quick throw connectionbetween said valve actuating means and said reversing valve.

12. The combination of a vehicle; a plurality of wind resistance vanes;means for guiding said vanes between active and inactive positions; ashiftable member; operative connections between said member and vaneswhereby shifting of the member shifts said varies in unison; areversible motor for shifting said member; a reversing valve controllingsaid motor; friction braking means; valve actuating means shiftableproportionally to the enersization of said friction braking means; aquick throw connection between said valve actuating means and saidreversing valve; and automatic means rendered eifective by intenseenergization oi! the friction braking means to reduce such energizationgradually.

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